Is there a service that can search for answers to general questions?
You can use Google

https://encrypted.google.com/search?hl=en&amp;q=when%20was%20Einstein%20born
and parse the response.

Wolfram ALPHA is another candidate.

http://m.wolframalpha.com/input/?i=what+year+was+Einstein+born&amp;x=0&amp;y=0

You can parse the returned html and see "Result:" div.